Card edge connector locking device

ABSTRACT

The invention is a locking device for locking circuit cards in zero-insertion force card edge connectors of the type having a vertically moving upper housing. More particularly, the locking device includes two pairs of pivotally mounted arms which are cammed inwardly from each side of the card. The upper nose-shaped ends of the arms enter holes in the card so that the card cannot be removed without actuating the camming mechanism.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention disclosed herein relates to devices for removably lockingprinted circuit cards in card edge connectors. More particularly, theinvention relates to zero insertion force card edge connectors havingsliding cam members to cam the contact elements against the traces onthe card and simultaneously to move the locking arms into holes in thecard.

2. Prior Art

The invention disclosed herein is a novel improvement and a departurefrom at least the following:

    ______________________________________                                        U.S. Pat. No.  Patentee   Class/Subclass                                      ______________________________________                                        3,573,706      Haberlen   339/17                                              3,970,353      Kaufman    339/75 MP                                           4,017,138      Evans      339/75 MP                                           ______________________________________                                    

Haberlen discloses a flat H-shaped leaf spring with the free ends of theupwardly extending legs having inwardly facing noses. The spring ispositioned in the card edge connector so that a card enters in betweenthe legs where upon the noses removably enter a hole in the card toretain it in the connector.

Kaufman discloses substantially the same type of locking device withdifferences being primarily in the way the device is positioned andretained in the connector. Both the Haberlen and Kaufman devices areshown as being used with high insertion force card edge connectors.

Evans discloses a locking device consisting of upright latch arms ateach end of a connector having a vertically moving member which cams thecontact elements into engagement with the traces on the card. The latcharms, each having facing hooks at the free ends, are cammed upwardly asthe moving member is pushed down so that the hooks move in over the topedge of the card to retain it in the connector. Additionally, releasearms are provided which lock the latch arms in the latched position and,upon being pushed inwardly, release the latch arms so that the card maybe withdrawn.

SUMMARY OF THE INVENTION

The invention disclosed herein comprises a pair of locking armspivotally mounted to the lower housing of a zero insertion force cardedge connector. The free ends of the arms extend upwardly into the upperhousing and are cammed in and out of the card slot as the upper housingis moved up and down. Nose-shaped free ends on the arms enter holes inthe card so that the card cannot be withdrawn from the connector withoutmoving the arms back out of the holes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view showing a zero insertion force connectorinto which the locking device of the present invention is incorporated.The drawing shows, in phantom, one pair of locking arms of the lockingdevice;

FIG. 2 is a cross-sectional view looking into the connector of FIG. 1from an end and shows the locking arms cammed out of the card slot; and

FIG. 3 is the same view as FIG. 2 but taken after the locking arms havebeen cammed into holes in a circuit card positioned in the card slot.

DESCRIPTION OF THE INVENTION

The invention disclosed herein is a locking device for removably lockingcircuit cards in a card edge connector. The locking device utilizes themechanism of a zero insertion force connector 10 shown in the severaldrawings. This connector has a lower housing 12, a vertically movingupper housing 14, camming mechanism 16 which, moving longitudinally,raises or lowers the upper housing through a series of ramps (notshown). Further, a plurality of contact elements (not shown) arepositioned in the connector. Upper beams (not shown) on the elementsextend upwardly into cavities 18 in the upper housing and as the upperhousing moves up, the beams are cammed in towards card slot 20 to bearagainst traces (not shown) on a card which may be positioned therein.

Under normal conditions, the beams exert enough pressure on the card sothat it does not move. This is not true under high vibrational forcesand the like which can cause the card to shift up and also movelengthwise in the slot. The latter motion must be guarded against toprevent short circuits and mismatch. Accordingly, the locking device ofthe present invention locks the card in the connector and prevents anymotion whatsoever. Further, the cards cannot be withdrawn without takinga positive step; i.e., actuating camming mechanism 16.

The locking device includes two pairs of identical, elongated arms 22with one pair positioned adjacent each end of card slot 20. FIG. 1 showsone pair of arms 22 in phantom.

With reference to both FIGS. 1 and 2, each arm is pivotally mounted atits lower end 24 in lower housing 12 with the pivoting direction beingtowards and away from the card slot; i.e., normal to the longitudinalaxis of connector 10. The mounting means may be pins 26 or the like.

Arms 20 extend upwardly into cavities 28 in the upper housing. Facingcavities are horizontally offset as shown in FIG. 1. The upper ends 30of the arms include a nose 32 located on the inside edge 34 so that itprojects in towards card slot 20.

Each arm includes a first follower 36 on side 38 and a second follower40 on opposite side 42. With the arms being identical, the firstfollower 36 and side 38 on one arm; e.g., the left-hand arm in FIG. 2,faces in the same direction as the second follower and side 42 on theother, facing arm; e.g., the right-hand arm in FIG. 2. The followers arelocated just below upper ends 30 of the arms so that they may beactuated by cam means located on sidewalls 44 of cavities 28 in upperhousing 14.

First follower 36 includes a downwardly facing, arcuate shoulder 46 andmerging therewith, outwardly facing edge wall 48. First follower 36rides along first cam surface 50 that includes a slanting but generallyhorizontal surface 52 and below that, a vertical wall 54.

Second follower 40 includes an upwardly facing arcuate shoulder 56. Thissurface rides along U-shaped second cam surface 58, the bight 60 ofwhich faces downwardly. As shown in FIGS. 2 and 3, the bight is slantingbut generally horizontal.

To reiterate, each arm has a first follower 36 on one side and a secondfollower on the opposite side. Being identical, arms in opposing (butoffset) cavities will offer different sides to a viewer looking into theconnector from an end; e.g., FIGS. 2 and 3. Similarly, cavity walls onone side of the arms carry different cam surfaces.

The operation of the locking device of the present invention will now beexplained.

In FIG. 2, connector 10 is in the open position; i.e., the upper beamsof the contact elements (not shown) are back in their cavities in theupper housing so that circuit card 62 was inserted into slot 20 withoutforce. Locking arms 22 are also retracted in their cavities 28.

To close connector 10, camming mechanism 16 (FIG. 1) is movedlongitudinally. Upper housing 14 is thereby moved vertically upwardly.Cam surfaces (not shown) in the contact element cavities 18 cam theupper beams in against traces on card 62. Simultaneously, locking arms22 are pivoted inwardly by first followers 36 riding against theupwardly moving first cam surfaces 50. The inwardly directed motion isbrought about by arcuate shaped, downwardly facing shoulder 46 riding onslanting surface 52. Since the angle that surface makes relative to thehorizontal is small, this inward motion is quite rapid. During thismotion, noses 32 enter holes 64 in card 62. Since the cavities 28 andthe arms are offset, the noses do not meet but rather slide by oneanother. As the upper housing continues to move, vertical wall 54 of camsurfaces 50 engages edge walls 48 of the first followers and holds thearms in the locking position shown in FIG. 3.

To open connector 10, camming mechanism is pushed back, causing upperhousing 14 to move downwardly to the FIG. 2 position. As it moves down,the upper beams on the contact elements move away from the card as dolocking arms 22 by means of second followers 40 riding along second camsurfaces 58. Second followers 40, riding up one side of the U-shaped camsurface 58, enters and travels along bight 60. The arms are thus pulledback and the noses retracted from holes 64. Note that the arms are heldin towards the slot for substantially most of the downward travel andonly near the end are the arms rapidly pulled back upon the arcuateshoulder 58 encountering and following bight 60. The card may be freelywithdrawn from the slot.

One of the advantages of this invention is that if for some reason theconnector is closed without a card in the slot, and then one tries toinsert a card, it will hit the upper ends of the arms and not the upperbeams which would, of course, damage them, probably beyond repair.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, as some modifications will be obvious to those skilled in theart.

We claim:
 1. A locking device for use with card edge connectors of thetype having a lower housing, a vertically moving upper housing, a cardreceiving slot and cavities normal to and opening into the slot, saidlocking device comprising:a. a pair of identical, elongated arms,pivotally mounted at their lower ends to the lower housing with thepivotal motion being normal to the card receiving slot, said armsextending upwardly into the cavities in the upper housing and having ontheir upper ends a nose which faces towards the slot; and b. a firstfollower on one side of each arm and cooperative cam means on the cavitywall adjacent thereto to pivot the arms in towards the slot as the upperhousing moves upwardly whereupon the noses enter holes in a card whichmay be in the slot to lock the card therein, and a second follower onthe other side of each arm and cooperative cam means on the cavity walladjacent thereto to pivot the arms out from the slot as the upperhousing moves downwardly whereupon the noses are withdrawn from theholes to unlock the card.
 2. The locking device of claim 1 wherein thefirst follower includes a downwardly facing, arcuate shoulder and thecooperating cam means on the cavity wall adjacent thereto includes aslanting but generally horizontal surface against which the arcuateshoulder follows to rapidly pivot the arm inwardly as the upper housingbegins to move upwardly.
 3. The locking device of claim 2 wherein thefirst follower further includes an edge wall extending upwardly from thearcuate shoulder and the cooperating means further include a verticalwall extending downwardly from the generally horizontal surface andagainst which the edge wall abutts to hold the arm inwardly towards theslot.
 4. The locking device of claim 1 wherein the second followerincludes an upwardly facing, arcuate shoulder and the cooperating cammeans on the cavity wall adjacent thereto includes a downwardly facing,slanting but generally horizontal surface against which the arcuateshoulder follows to rapidly pivot the arm away from the slot as theupper housing nears the end of a downward travel.
 5. The locking deviceof claim 4 wherein the second follower further includes an edge wallextending downwardly from the arcuate shoulder and the cooperating meansfurther includes a vertical wall extending downwardly from the generallyhorizontal surface with the edge wall bearing against the vertical wallto hold the arm in towards the slot for substantially most of thedownward travel of the upper housing. .Iadd.
 6. A locking device for usewith card edge connectors of the type having a lower housing, avertically moving upper housing, a card receiving slot and cavitiesnormal to and opening into the slot, said locking device comprising:a. apair of identical, elongated arms pivotally disposed in the lowerhousing with the pivotal motion being normal to the card receiving slot,said arms extending upwardly into the upper housing and having on theirupper ends a nose which faces towards the slot; and b. a first followeron one side of each arm and cooperative cam means on the cavity walladjacent thereto to pivot the arms in towards the slot as the upperhousing moves upwardly whereupon the noses enter holes in a card whichmay be in the slot to lock the card therein, and a second follower onthe other side of each arm and cooperative cam means on the cavity walladjacent thereto to pivot the arms out from the slot as the upperhousing moves downwardly whereupon the noses are withdrawn from theholes to unlock the card. .Iaddend.